A rechargeable battery, for example, a lithium-ion battery, is installed in a vehicle such as an electric vehicle (EV) or a plug-in hybrid vehicle (PHV). The rechargeable battery is a power storage device that stores power, which is supplied to an electric motor functioning as a prime mover. The rechargeable battery includes an electrode assembly and a case, which accommodates the electrode assembly. The electrode assembly is formed by stacking a positive electrode, which includes a positive electrode active material layer, and a negative electrode, which includes a negative electrode active material layer, with a separator located between the positive electrode and the negative electrode. Patent document 1 discloses a structure that uses fastening tapes to fasten the electrodes and the separators of the electrode assembly.
To improve the contact properties of each electrode and limit displacement of the electrodes, load may be applied in a stacking direction of the electrodes to regions where the active material layers are opposed to one another. Also, expansion of the electrode assembly during charging and discharging may result in the case applying load to the opposing regions. Further, in an assembled battery in which the rechargeable batteries are stacked and connected in series to one another, a constraining load may be applied to the rechargeable batteries in the stacking direction.
In a rechargeable battery in which a fastening tape is applied to the electrode assembly, an edge of the fastening tape forms a step on the surface of the electrode assembly. In this case, the above load has a tendency to concentrate on the step formed by the fastening tape. This may cause uneven load to be applied to the opposing regions from the case.